Catheter and a method and an apparatus for making such catheter

ABSTRACT

The present invention concerns a catheter for medical purposes, such as for insertion into a body opening for draining fluids, wherein the catheter comprises a flexible tube having a distal end region wherein the tube is provided with at least one draining opening, characterised in that the peripheral edge on the outside of the tube is provided with a curvature for creating a smooth transition between the exterior surface of the tube and the substantially radially oriented cut constituting the opening side and wherein said curvature is a rounded edge with a curvature radius between 0.2-0.6 mm. The invention further concerns a method of making such catheter and an apparatus for performing this method.

The present invention relates to a method of making a catheter formedical purposes, such as for insertion into a body opening for drainingfluids, wherein the catheter comprises a flexible tube having a distalend region wherein the tube is provided with at least one drainingopening. The invention further relates to an apparatus for performingsuch method.

A catheter includes a flexible tube with a distal end, which may be openor closed. The catheter is inserted into a body opening for drainingfluids. In particular, the catheter may be a urinary catheter forinsertion into a urinary pathway for collecting the fluids in thispathway.

In the distal end region of the catheter, the tube is provided with anumber of openings for colleting fluid and draining the body opening, inparticular the urinary pathway. A catheter of such kind is known frome.g. U.S. Pat. No. 5,919,170. As shown in this U.S. patent, the openingsare preferably elongated to achieve a good fluid collecting capacity.These openings are usually punched into the tube. Examples of suchcatheters are known from e.g. GB-A-2 230 702 and U.S. Pat. No.3,995,518.

U.S. Pat. No. 2,972,779 discloses two methods of providing the wall of atubing of thermoplastic material with elongated holes having a smoothedouter edge. According to one method, the elongated holes are punched outand subsequently the edge is smoothed out in an operation whereby amoving grinding element, such as a rotating grinding wheel, is contactedwith the sharp edge of the hole. According to another method, theelongated holes and their smooth edges are provided by punching andmoulding by means of a metallic die having a punching element.

US 2005/0192560 A1 describes a method of providing a urology catheter bymeans of injection moulding. The catheter is provided with a drain eyein the wall of the tubing forming the body of the catheter. The innerand outer edges of the drain eye are smoothed out by forming radiibetween the wall of the drain eye and the inner and outer wall,respectively, of the tubing.

US 2004/0193143 A1 describes the forming of openings in a catheter by apunching operation. The openings may be rounded by a temperaturetreatment.

U.S. Pat. No. 4,259,276 describes a method of forming circular holes inthin plastic material. The method is exemplified by the forming oflateral holes in a cannula for epidural anaesthesia. Firstly, a needleis forced along its length through the wall of a nylon tubing to form apierced aperture in the wall. The needle is withdrawn from the aperture,and drive is applied to the needle to rotate the needle at high speedabout its longitudinal axis. The needle is then inserted into thepierced aperture without any drive being applied to the needle, so thatcontact of the rotating needle with the rim of the aperture producesfrictional heating that serves to cause plastic flow smoothing out thecontour of the pierced aperture around the needle.

GB 2 230 702 A describes injection moulding of a catheter havingelongated holes with rounded ends.

The catheter must be carefully inserted and removed to avoid damagingthe tissue of the pathway. This can be a problem with these knowncatheters, since the openings have a relatively sharp edge which candamage the soft tissue of the pathway when the catheter is movedlongitudinally or rotated in the pathway during inserted or retracted.The catheters are usually produced in PVC or PUR so that a soft flexibletube is provided thereby reducing the risk of tissue damage. However,practical experience with the catheters have revealed that in particulartissue of a urinary pathway may nevertheless be damaged if the catheteris not carefully inserted or retracted from the pathway.

This problem is addressed by a method of making a catheter according tothe present invention, wherein the catheter comprises a flexible tubehaving a distal end region wherein the tube is provided with at leastone draining opening, wherein the peripheral edge on the outside of thetube is provided with a curvature for creating a smooth transitionbetween the exterior surface of the tube and the substantially radiallyoriented cut constituting the opening side and wherein said curvature isa rounded edge with a curvature radius between 0.2-0.6 mm. By theinvention, the opening in the tube is provided with a three-dimensionalcontour in a curved plane congruent with the curvature of the opening inthe cylindrical surface of the tube. Hereby, a smooth catheter isprovided where the risk of tissue damage is reduced.

The opening is preferably elongated with a longitudinal lengthsubstantially corresponding to the diameter of the tube. The cathetertube may be provided with different diameters so that different sizes ofcatheters may be provided. The drainage openings in the catheter tubeare preferably provided with an angle between the opening side wall andthe internal surface of the tube is within the range of 64-90°. Thisprovides the catheter with good drainage properties as well as tissuepreserving properties.

The catheter tube is made of a medical grade polymer preferably having aShore A value in the range of approx. 64 to approx. 100, in particularthe polymer may be a thermoplastic material, such as a polyester-typethermoplastic polyurethane (TPU) compound having a Shore A value ofapprox. 94±3, polyvinylchloride (PVC), preferably having a Shore Ahardness ranging from 78 to 85, or polyurethane (PUR). By the invention,it is realised that a variety of materials are suitable for thecatheter. For instance, the catheter tube may be of polyvinylchloride(PVC) with a hardness measured in Shore A with a value of 64 to 86,preferably 80 to 85 Shore A.

By the invention, there is also provided a method of making a cathetercomprising a polymer tube with openings therein, said method forproviding openings in a polymer tube of such catheter comprising thesteps of:

-   -   providing a tube and punching at least one opening in the tube        by advancing a cutting member in a substantially radial        direction into the wall of the tube;    -   manipulating the outer peripheral edge region of the at least        one opening by rounding the peripheral edge of the punched        opening in the tube by advancing a heated forming member into        the opening and thereby providing the edges of the opening with        a shape corresponding to the shape of the distal end of the        forming member, said forming member having a distal end adapted        for engagement with an opening of the tube provided adjacent        said distal end, wherein said distal end of the forming member        is provided with a rounded shoulder transition at the foot of        the distal end and with a protrusion extending from said        shoulder transition region, said protrusion having a form        fitting the opening in the tube, said rounded shoulder being        formed with a contour in a curved plane congruent with the        curvature of the opening in the cylindrical surface of the tube.

By finishing the opening in a separate after treatment process, thesmooth curvature of the edge of the drainage opening is ensured.

In a preferred embodiment of the method, the loose cut-away materialafter the punching action is removed from the tube. Hereby, it isensured that residues from the making of the opening do not drop intothe inside of the catheter tube.

According to the invention there is also provided an apparatus formanipulating openings in a polymer tube for manufacturing a catheter,said apparatus comprising a movable frame comprising one or more formingstations, each forming station being adapted for receiving a flexiblepolymer tube with at least one opening therein through the station andeach forming station comprising a forming member, which is mounted infloating arrangement in said forming station, said forming member havinga distal end adapted for engagement with an opening of the tube providedadjacent said distal end, wherein said distal end of the forming memberis provided with a rounded shoulder transition at the foot of the distalend and with a protrusion extending from said shoulder transitionregion, said protrusion having a form fitting the opening in the tube,said rounded shoulder being formed with a three-dimensional contourcongruent with the curvature of the opening in the cylindrical surfaceof the tube, and heating means for said forming member, so that saidforming member may be heated to a temperature above the softening pointof the polymer of the tube and preferably below the melting point of thepolymer material of the tube.

In order to ensure a smooth result of the plastic deformation of theedge region of the opening in the tube, the distal end of the formingmember is provided with a rounded shoulder transition at the foot of thedistal end and with a protrusion extending from said shoulder transitionregion, said protrusion having a form fitting the opening in the tube,said rounded shoulder being formed with a three-dimensional contourcongruent with the curvature of the opening in the cylindrical surfaceof the tube.

The rounded shoulder region is provided with a curvature radius between0.2-0.6 mm and preferably the protrusion is elongated with alongitudinal length substantially corresponding to the axial extensionof the opening on the tube.

In the preferred embodiment, the forming member is provided in a formingstation which is arranged in a movable frame, and each forming stationis adapted for receiving a flexible polymer tube through the station,and whereby the forming member is mounted in floating arrangement in aforming station, whereby the forming member is self-aligning when theprotrusion is engaging the opening of the tube. This floatingarrangement allows for inaccuracies in the positioning of the openingrelative to the forming member.

The movable frame preferably comprises an upper section and a lowersection where between the at least one forming station is arranged andthe upper section is heated to a first temperature, such as 190°-200°C., and the lower section is heated to a second temperature, such as170°-180° C., which is lower than the first temperature. The holdingtime of the forming member in contact with the tube is preferably 1 to 5seconds, more preferably between 1.5 and 2.0 sec. Since there inherentlyis a heat loss between the movable frame and the shoulder and tip of theforming member, the temperatures applied to the upper and lower sectionsare somewhat higher than the preferred temperature which is between thesoftening point of the polymer of the tube and below the melting pointof the polymer material of the tube. This ensures that the deformationof the edge does not result in any deterioration of the surface textureand the material of the tube, e.g. burns or uncontrolled deformations.The forming member is made of metal, such as brass or similar heatresistant material that can withstand the applied heat. By the inventionit is realised that the temperature may be even above the melting pointof the tube material if the holding time is kept very low, such as below1.5 seconds.

It is realised that the predetermined temperatures and the holding timesare selected in accordance with the specific plastic material used forthe tube.

In the following the invention is described with reference to somepreferred embodiments shown, in the accompanying drawings, in which:

FIG. 1 is a side view of a catheter of the kind the present inventionconcerns;

FIG. 2 is a detailed view of an axial cross-section of the tip of acatheter according to the invention;

FIG. 3 is a detailed view of a radial cross-section of the tip of acatheter according to the invention through the section B-B in FIG. 2;

FIG. 4 a)-e) are further views of a catheter according to the invention;

FIG. 5 is a perspective view of the catheter of FIG. 4;

FIG. 6 is a detailed perspective view of the opening after punching butbefore the rounding process according to the invention,

FIG. 7 is the same as FIG. 6, but after the method of the invention isperformed;

FIGS. 8-10 are three side views of a forming member in an apparatus formaking the catheters according to a preferred embodiment of theinvention;

FIG. 11 is a side view of a forming member of a smaller size than theforming member shown in FIG. 9;

FIG. 12 is a schematic end view along the catheter tube with twooppositely situated forming members in engagement in the drainingopenings;

FIG. 13 is a section view along A-A in FIG. 12;

FIG. 14 is a schematic side view of the catheter tube with twooppositely situated forming members in engagement in the drainingopenings;

FIG. 15 is a section view along B-B in FIG. 14;

FIG. 16 is a section view along C-C in FIG. 14; and

FIG. 17 is a schematic front view of a forming station in a moveableframe in an

apparatus according to the invention;

FIG. 18 is a cross-sectional front view of the forming station in FIG.17;

FIG. 19 is a cross-sectional side view of the forming station in FIG.17; and

FIG. 20 is a detailed perspective view of the geometry of the distal endof the forming member and the opening in the tube.

With reference to FIGS. 1 to 5, a catheter according to the inventioncomprises a flexible tube 1, which is made of a plastic material,preferably polyvinylchloride (PVC) or polyurethane (PUR) and attached toa connector 2. The tube 1 is provided with a number of openings 3 inregion of the distal end 4 of the tube 1. This opening 3 serves a drainfor collecting fluids outside the tube to flow inside the catheter tube1 for draining the body space in which the catheter is inserted. Theopening 3 has a generally radially oriented side wall 5 (see FIG. 3),and which may be provided with an angular orientation v of between60-90° relative to the inner surface of the wall of the tube 1 (see FIG.2). The opening 3 may involve a slight indentation 6 into the tube innerspace. This indentation 6 may be between 0-0.5 mm. The hole 3 isprovided with rounded external edges 7, so that a smooth transitionbetween the opening walls 3 and the surface of the tube 1 is ensured.

The openings 3 are punched in the tube using a punching tool (not shown)or other cutting tool. After the opening 3 is cut in the cuttingprocess, the loose tube wall section is removed leaving an opening inthe tube 1 where the opening 3 has a sharp outer edge, as shown in FIG.6. By the finishing process according to the invention, the outer edgeis rounded as shown in FIG. 5 and FIG. 7.

For providing the rounded edge 7 on the opening 3, a moveable frame 20is used, see FIGS. 17 to 19. The moveable frame includes one or moreforming stations, where each forming station is adapted for receiving aflexible polymer tube 1 through the station adjacent a forming member10. The forming station further includes a holding member 11 to whichthe forming member 10 is fixed. This member is connected to an uppersection 21 of the frame 20 by a spring arrangement 26. The holdingmember 11 is furthermore pivotably connected to the distal ends of afork-like member 12, so that the fork-like member 12 and the holdingmember 11 may pivot relative to each other about an axis A substantiallyperpendicular to the tube 1 above the tube 1. The fork-like member 12 isat its base pivotably connected to a third member 13, where the twomembers 12, 13 may pivot about an axis B substantially parallel to thetube 1 below the tube 1. This third member 13 is then pivotablyconnected to a lower member 14 allowing these members 13, 14 to pivotabout an axis C substantially perpendicular to the tube 1. This lowermember 14 is preferably vertically slidably secured to a lower section22 of the frame via a spring 25. When the frame 20 is moved relative tothe tube 1, the forming member 10 is moved in engagement with theopening 3 in the tube 1. By the pivoting arrangements, the formingmember 10 is floatingly arranged in the frame whereby the forming member10 may be self-centering in the opening 3.

With reference to the FIGS. 8-10 and 11, the forming member 10 has adistal end 33 adapted for engagement with the opening 3 of the tube 1provided adjacent the distal end 33. The distal end 33 of the formingmember 10 is provided with a rounded shoulder transition 32 at the footof the distal end 33 and with a protrusion 31 extending from theshoulder transition region 32. The protrusion 31 has a form fitting theopening 3 in the tube 1. The rounded shoulder 32 is formed with athree-dimensional contour congruent with the curvature of the opening 3in the cylindrical surface of the tube 1. It is important to realisethat the edge 7 of the opening on the tube 1 extend in a curved plane,i.e. the edge 7 has a three-dimensional extension. As shown in figs. 9and 11, the forming member 10 may be provided with different distal endsin order to adapt a forming member to a specific tube and opening size.

By applying heat to the frame and thereby to the members in the formingstation, which are all made of a thermally conductive material,preferably steel or similar metal, the forming member 10, which is madeof brass or the like, is heated to a temperature above the softeningpoint of the polymer of the tube and preferably below the melting pointof the polymer material of the tube. A first heat source 23 is applyingheat to the upper section 21 of the frame 20 and a second heat source 24is applying heat to the lower section 22 of the frame 20. The firsttemperature may preferably be between 180-200° C.±10° C. and the secondtemperature may be between 170-190° C.±10° C. The diameter of the tubemay be between 2.0-6.0 mm and the temperature applied is preferably inthe lower range of the temperature range if the diameter is small. Thetemperature ranges as well as the holding times may vary depending onthe type of material and the thickness of the tube wall as well as thediameter of the tube.

When heat is applied to the forming station and thereby to the formingmember TO the forming member 10 is advanced into engagement with theopening 3 in the tube 1 for a predetermined period of time, preferablybetween 1.5-2.0 seconds. The temperatures applied and the times ofengagement, i.e. the holding time, are selected in accordance with thetube material and the tube dimensions. The temperature may be even abovethe melting point of the tube material if the holding time is kept verylow. Hereby, the edge 7 is rounded in a plastic deformation process asthe heated forming member 10 is moved into engagement in the opening 3.The protrusion 31 fits into the opening 3 and as the protrusion alignsin the opening 3, the rounded transition 32 thereby advances correctlytowards the edge region and thereby creates the desired rounding of theedge 7. The floating arrangement described earlier facilitates thealignment of the forming member 10 in the opening.

As shown in FIGS. 12 to 16, two openings in a catheter made can beprocessed simultaneously by having two movable frames (not shown)adjacent each other so that a first forming member 10′ is advanced intocontact with an opening from a first side of the tube and a secondforming member 10″ is advanced into contact from a side opposite thefirst side.

The form of the edge 7 of the opening 3 in the tube 1 is determined bythe geometry of the distal end of the forming member 10, in particularthe shoulder transition 32 but also the protrusion 31. The resultingtube opening 3 may be provided with an inclined side surface 5 with anangle v between 60°-90° in the axial direction between the opening sideand the inner surface of the tube 1, see FIG. 2. As shown in FIG. 3, theside walls 5 of the opening 3 may have a radial direction in thecross-sectional direction. Moreover, a slight inwardly extendingindentation 6 having a radial extension between 0-0.48 mm is alsoprovided in the tube.

EXAMPLES

For different diameter sizes, tests have been made for finding asuitable relationship between temperature, holding time and pressure ofthe forming member 10. In practise, the pressure may be predetermined asthe insertion depth of the distal end of the forming member 10 and maybe controlled in relation to the predetermined measurements andtolerances. By testing, the chosen combinations of temperature and timelisted in table 1 below are found stabile for manufacturing and optimalwith respect to minimizing the process time.

The parameters for the tests were:

-   -   The tube material was ESTANE 58212 TPU which is a thermoplastic        polyurethane compound with a glass transition temperature of        −25° C., an extrusion temperature of 200-210° C. and an        injection moulding temperature of 195-205° C.    -   The shape and the temperature of the distal end of the forming        member.    -   The time the forming member is making contact with the tube.    -   The insertion depth of the distal end of the forming member in        the tube, referred to as pressure).

TABLE 1 ESTANE ® 58212 TPU Diameter size Temp. Time CH08 170° C. 1.5 sCH10 180° C. 1.7 s CH12 180° C. 1.7 s CH14 180° C. 1.7 s CH16 180° C.1.7 s CH18 180° C. 2.0 s

Compared to the parameters in table 1, by lower temperatures or shortertime or lower pressure (i.e. shorter insert distance) it was found thatthe rounding was not complete and/or the deformation was not permanent.

Compared to the parameters in table 1, by larger temperatures, thematerial became too liquidized and melted and by longer time or largerpressure resulted in elevated edges in the transition between the tubeand the forming member 10.

In relation to the geometric shape of the distal end of the formingmember 10 it was found of imperative importance that the rounding of theedge is a stamp of the forming member by a certain deformation of thetube. Accordingly, the shape of the distal end of the forming member isof most importance for obtaining a satisfactory rounding of the edge ofthe catheter opening 3. By matching the three-dimensional contour of theedge on the tube when shaping the distal end of the forming member, i.e.with the same dimensions, rounding and sizes, a satisfactory result wasconsidered achieved. Moreover, by forming the distal end of the formingmember with appropriate angles and transitions it was found furtherensured that no “sharp” edges would occur on the tube.

As indicated in FIG. 20, the contour of the shoulder transition portion32 of the distal end 33 of the forming member 10 are shaped with two endsections 34 with a “straight” section 35 there between. Thecorresponding edge contours are marked on the tube opening 3 by 34′ and35′, respectively. Whereas the straight section 35 is substantially inthe same plane, due to the cylindrical shape of the tube and the centralstraight shape of the opening when viewed from the Y-axis, the ends 34,34′ are curved out of this plane because of the rounded, semi-circularend portions of the opening again when viewed from the Y-axis. Thisthree-dimensional shape of the distal end of the forming member 10 isfound particularly advantageous in order to achieve an opening 3 with anentirely and truly smooth contour.

This geometry ensures that an unacceptable deformation on the inside ofthe tube is prevented.

The resulting rounded edge along the opening in the catheter tube is inan X-Y and/or Y-Z plane. When viewing the catheter in the Z-direction,such as shown in FIG. 2, FIGS. 4 c and 4 e, it becomes apparent that thecontour of the edge of the opening 3 is curved in an X-Y planeperpendicular to the rounded edge plane at any given place on along theopening. This curvature of the side contour of the opening is due to thecylindrical form of the tube. This in turn means that when the openingis cut the central section, i.e. the straight section 35′ in FIG. 20,becomes lower that the outer contour of the tube view viewed from theside, e.g. as schematically shown in FIGS. 4 a, 4 c and 4 e. The endsections of the opening, i.e. the extremes in the X direction of theopening, curve outwards towards the straight outer contour of the tubeitself. By the invention it is realised that it is important toacknowledge and pay attention to this geometric shape when forming therounded edges on the opening in order to avoid sharp edges and to ensurea truly smooth transition between the outer surface of the cylindricaltube and the inner side wall 5 of the opening 3.

Above, the invention and the different aspects thereof are describedwith reference to some preferred embodiment. However, by the inventionit is realised that other variations and equivalent solutions may beprovided without departing from the scope of the invention as defined inthe accompanying claims, such as other suitable materials and otherprocess parameters, such as temperature and time, may be chosen in orderto achieve a satisfactory result when using tubes in a predeterminedmaterial.

The catheter according to the invention may be a urinary catheter, atracheostomy catheter or any other type of catheters for insertion intoa body cavity for draining fluids.

1. A method of making a catheter comprising a polymer tube with openingstherein, said method comprising: providing a tube and punching at leastone opening in the tube by advancing a cutting member in a substantiallyradial direction into the wall of the tube, and providing the at leastone opening with a three-dimensional edge contour, whereby central,straight sections of the edge contour of the opening become lower thanthe outer contour of the tube, when the tube is viewed from the side,and end sections of the edge contour of the opening curve outwardstowards the straight outer contour of the tube itself; manipulating anouter peripheral edge region of the at least one opening by rounding theperipheral edge of the punched opening in the tube by advancing a heatedforming member a predetermined distance into the opening and providingthe peripheral edge of the opening with a shape corresponding to a shapeof a distal end of the forming member, said distal end of the formingmember is provided with a rounded shoulder transition portion at a footof the distal end and with a protrusion extending from said shouldertransition region, said protrusion having a form fitting the opening inthe tube, said distal end of the forming member being shaped so that itmatches the three-dimensional contour of the edge of the punched openingin the tube, a contour of the shoulder transition portion of the distalend of the forming member is shaped with two end sections withsubstantially straight sections therebetween, corresponding to the endsections and the central straight sections of the edge contour of theopening, respectively, the substantially straight sections of thecontour of the shoulder transition portion extend substantially in thesame plane, of the contour of the shoulder transition portion curve outof said plane; holding said heated forming member in said advancedposition for a predetermined holding time; and retracting the formingmember.
 2. A method according to claim 1, further comprising removingloose cut-away material after the punching action.
 3. A method accordingto claim 1, further comprising providing the forming member in a formingstation positioned in a movable frame the forming member is mounted infloating arrangement in the forming station, the forming member isself-aligning when the protrusion is engaging the opening of the tubereceived in the forming station.
 4. A method according to claim 1,comprising heating an upper section of the movable frame to a firsttemperature and heating a lower-section of the movable frame to a secondtemperature with the forming station between the upper section and thelower section the second temperature is lower than the firsttemperature.
 5. A method according to claim 1, comprising providing thedistal end of the forming member with a rounded shoulder transition witha curvature radius between about 0.2-0.6 mm at the foot of the distalend and with a protrusion extending from said shoulder transition regionwhich is inserted into the opening of the tube, and providing theprotrusion is provided with a form fitting the opening in the tube, andforming the rounded shoulder with a three-dimensional contour congruentwith the curvature of the opening in the cylindrical surface of thetube.
 6. A method according to claim 1, comprising providing the tubemade of a medical grade polymer having a Shore A value in the range ofabout 64 to about 100, and heating the forming member to a temperatureabove the softening point of the polymer of the tube and below themelting point of said polymer.
 7. An apparatus for manipulating openingsin a polymer tube for manufacturing a catheter, said apparatuscomprising: a forming member, having a distal end adapted for engagementwith an opening punched in the tube provided adjacent said distal end,wherein said distal end of the forming member is provided with a roundedshoulder transition portion at a foot of the distal end and with aprotrusion extending from said shoulder transition portion, saidprotrusion having a form fitting the opening in the tube, said openingpunched in the tube being provided with a three-dimensional edgecontour, whereby central, straight sections of the edge contour of theopening are lower than the outer contour of the tube, when the tube isviewed from the side, and end sections of the edge contour of theopening curve outwards towards the straight outer contour of the tubeitself, and heating means to heat said forming member to a temperatureabove the softening point of the polymer of the tube, said distal end ofthe forming member has a contour shaped to correspond to thethree-dimensional contour of the edge of the punched opening in thetube, wherein substantially straight sections of the contour of the ashoulder transition portion of the forming member extend substantiallyin the same plane, and end sections of the contour of the shouldertransition portion curve out of said plane.
 8. An apparatus according toclaim 7, wherein said apparatus comprises a movable frame comprising oneor more forming stations, each forming station being adapted forreceiving a flexible polymer tube with at least one opening thereinthrough the station and each forming station comprising a forming memberthat is mounted in floating arrangement in said forming station.
 9. Anapparatus according to claim 7, wherein the forming member isself-aligning when the protrusion is engaging the opening of the tube.10. An apparatus according to claim 7, wherein the movable framecomprises an upper section and a lower section where between the atleast one forming station is arranged.
 11. An apparatus according toclaim 7, wherein the forming member is made of metal.
 12. (canceled) 13.An apparatus according to claim 7, wherein the rounded shoulder portionis provided with a curvature radius between about 0.2-0.6 mm.
 14. Anapparatus according to claim 7, wherein the protrusion is elongated witha longitudinal length substantially corresponding to the axial extensionof the opening on the tube.
 15. An apparatus according to claim 7,wherein the tube is made of a medical grade polymer, comprising athermoplastic material.
 16. (canceled)
 17. A catheter for medicalpurposes, such as for insertion into a body opening for draining fluids,the catheter comprising: a flexible tube having a distal end regionwherein the tube is provided with at least one draining opening, aperipheral edge on an outside of the tube is provided with a curvaturefor creating a smooth transition between an exterior surface of the tubeand a substantially radially oriented cut constituting an opening sideand wherein said curvature is a rounded edge with a curvature radiusbetween 0.2-0.6 mm, and said rounded edge is formed in a curved planefollowing the curvature of the opening in a cylindrical surface of thetube, and wherein the tube is made of a medical grade polymer having aShore A value in the range of about 64 to about
 100. 18. A catheteraccording to claim 17, wherein the opening is elongated with alongitudinal length substantially corresponding to the diameter of thetube.
 19. A catheter according to claim 17, wherein the polymer is athermoplastic material comprising a polyester-type thermoplasticpolyurethane (TPU) compound, polyvinylchloride (PVC), having a Shore Ahardness ranging from about 64 to 85, or polyurethane (PUR).
 20. Acatheter according to claim 17, wherein the angle between the openingside and the internal surface of the tube is within the range of about64-90°.
 21. The method of claim 1 wherein the predetermined holding timeis about 1 to 5 seconds.
 22. The apparatus of claim 15 wherein thethermoplastic material comprises a polyester-type thermoplasticpolyurethane (TPU) compound having a Shore A value in the range of about80 to 100, polyvinylchloride (PVC), or polyurethane (PUR).